Welding roll



April 19, 1932. J, V, CAPUTO 1,854,924

WELDI NG ROLL Filed Aug. 29, 1930 INVENTOR '5 ods and devices ther the edges of a seam cle ina cylmp ical tube forme 10 sizes, I have mvented means li tric welding machine.

lsions o the ipe,

-eratureisdesired heating of' ling,en,ga ge the Patented Apr. 19, 1932 UNITED STATES unies v. or einem), omo

'W'H'DING ROLL appunti mea kunt as, 1930. swarm.. 478,610.

M invention relates to welding and, in partlcular to continuous electric welding as produced ty .the resistance met a In the prior art there are disclosed numerous methfor continuousl welding tod continuously. from a ilat strip. While the disclosures of this art relate principally to thin gauge tubing of small similar advantages in the manufacture of large-size heavy-wallA pipe, which are disclosed in my co-pending application, Serial No. .475 174, filed August 14, 1930, for ElecvIn the weldngfof large size pipe, itis necessaryl to employ currents of greatmagnitude.l T e larger dimenfurthermore, tend to magl culties encountered in the continuous welding of thin gauge material.

One of the diiliculties that has been encountered heretofore is the tendency of the welding current to be shunted around the solid portion ofthe' formed tube without passmg across the seam. y

It is common practice t0 supply welding seam y a pair or'A rolls rigidly secured together but edges of the seam cleft and the current p thereacross heats the edges 'to the welding temperature.

current in parallel w1th that fora welding the ' across the seam is 'provided by the solid continuous section o the formed tube; This parallel 2th shunts a portion of the welding y current m the seam where the high temppipe where it :is not wanted. This shunting of the welding current results in undesirable the seam cleft; An extra load is als'oplaced .upon the current supplying equipment wh1ch result.

condition is aggravatedbecause the hichf are employed `to force cleft together for'weld- 4 substantially the same urrent supplying electrode ees no`use rod plane as the 5 rolls. The framewpzirlzv of the pressure rolls for obtaining' through the pressure from each other. The rolls engage A low resistance" path tion;

to the solid section ofthe the tube at .portions other than'- thus supplies a further parallel vpath forthe welding current, which increases the diiiiculty hereinabove described.

VAnother objectionable result of the current shunted around the solid section of the ipe without passing across the seam is that it induces corresponding currents in .the pressure rolls. These currents not only tend to heat' the pressure rolls unnecessarily but by transformer action lessen the reactance of the shunting current/path in-the pipe so thatk still more shunting current iiows.

I have avoided the diiiiculties above mentioned by providing a side pressure roll for a cntinuouswelding machine, which is made up of a plurality of laminations. I also insulate the laminated rolls from the frame in `which they are mounted for cooperation with a rotary drive. The provision of laminated rolls increases the reactance opposing thel flow of shunted circulating current and, at the same time, prevents the flow of induced or eddy currents in the roll itself. The insulation prevents the circulation of current roll frame.

In order to insure pipe firmly, I provide roll faces with a slight recess intermediate the ends of the'lolls.

For a complete understanding of the invention, reference is made to the accompanyin drawings in which igure 1 is a partial side elevation of the pressure Toll stand of a continuous electric welding machine, part being-shown in sec- Figure 2 is laminated rolls; and A Figure 3 is a section on of Figure 2. Referring in detail to the drawi'n s, a pipe is formed from a .'iiat plate of s elp and positioned so that the abutting edges thereof are adapted to be engaged by'elec'trode rolls the line III-III 11 and 12, whilethe pipe is passedthrough a.

pressure roll stand 13 comprising side rolls 14 and 15 and a lower support roll 16. The electrode rolls 11 and 12 are suitably supported-for rotation above the pressure rolls 14 and 15. As willbe apparent from Figure l, the welding current iiowing, say, from the that the roll grips 'the a side elevation of one of the 'l l roll 11 toward the roll 12 may traverse a path directly across the seam cleft in the Eipe -or ma pass around the solid section of t e pi e Wit out crossing the seam. Since it is -on y the current that crosses the seam which raises it to welding temperature, it is desirable to limit the shunting currentas much as possile. The rolls 14 and 15-must have intimate contact with the pipe so as to exert lateral pressure thereon and must be of long wearlng material. Solid steel rolls have been employed in the past but these the circulationof large shunting currents 'through the solid section of the pipe 10. order to avoid this characteristic of solid steel rolls, the frame has rolls 14, 15 and 16 formed. from a lurality of laminations 17 punched from -t in steel sheets such 20 as are employed in building up transformer cores. The laminations 17 are secured together with end plates 18 and 19. A'series of bolts 20 and 211hold the end plates and laminations together. ably insulated from the laminations by insulating bushings 22. As is wellknown, the f usual oxide and lacquer coats on transformer sheets serve to insulate them fromeach other. After the laminations and end plates have been assembled and bolted together, the en a 'ng groove 23 is theg rll and a ltapered slot is rovided. The rol s 14 and 1 5 are keyed on shafts 26 and 27 which are rotatably 'journaled in roll housings 28 and 29. insulating bushing 3g parates fthe rolls from their supporting s a Y f1 turned in the face of bore 24 having a key The housings 28 and 29 are slidably sup--A ported in a frame 31 resting on a base 32. r Adjusting screws 33 permit the housings to 'be advanced toward or retracted from the L axis ofthe pipe 10. The' housin worm wheels .-34 and worms 35. T e have sliding engagement with 36 driven from any suitable power source 37` The side rolls 14 and/15 thus serve to advance the pi e through th welder as well as to force t e edges of the seam cleft together. A

e lower supportin construction to the ro keyed on a shaft 38 and by an insulating bushin 39. The shaft38 is journaled 'a vertica ly adjustable housing 40 and an adjusting screw 41 is provided for raising or lowerin the housing.

. e mechanical detalls .of the pressure roll stand 13 have been described in co-pending application referred' 00 1 and tained latter a square shaft s 14 and 15. Itis to onlpage only so much ofthe dcription con! therein as is necessary for a complete understanding of the present invention is re pea`ted here.

The rolls 14, 15 and 16 are each provided u with an ann curved surface of rent path.

rolls permitted' The bolts are prefer-v lpipe more, prevents any y. duced roll 16 is similar in separated therefrom h full vin my t engaging the ular recess 42 so that the edges Langeac of the roll will firmly engage and grip the the pipe.

It will be obvious that the laminated roll illustrated and described is characterized by a greater reactance opposing the flow of shunting current than would be the case in the solid rol e reactane o posing the flow of shunting current in t e pipe, of course, depends on the reluctance of the magneticcircuit in the material adjacent the cur- Since the roll is laminated in a plane perpendicular to the tangent to the pipe at the point at which the roll engages therewith, current tending'to traverse the unting path through the solid pipe section induces a large amount of flux in the laminations of the' roll. This flux opposes the flow of current through the shunting path.

In a solid roll, currents are induced in the solid face of the roll in opposite directions to that inthe pipe section by transformer ac` tion. The existence of these currents in the face of the roll lowers the reactance o posing .the How of circulating current, wit lthe result that still more current is shunted around the pipe. Since the laminations of the rolls are insulated from each other, no current can traverse theroll face as the result of induction by the current in the shuntin ath. t

l ve lthus reduced-the amount of shunting current in two ways, first'by increasing the lreactance opposingthe flow of shunting current, and second by preventingthe flow of induced currents in the roll face which 1 would tend to permit larger circulating currents to flow in the pipe.

The insulation of the" rolls from their shafts andthe supporting frames, further-` circulating lcurrent from 1 traversing the bearing or frame structure.

e circulating current is thus further reand'the result is that substantially all of the current suppliedto the pipefrom the rolls 11 and 12 crosses the seam cleftl in the pipe 10 to raise the temperature of the edges thereof tothe welding point. All unnecessary heating of the body of the -pipe and the faces of the pressure rolls by the circulation of shuntin currents is eliminated.

Althoug I lhave illustrated and described erein but one `present preferred embodiment of the invention, it is obvious that other constructions ma be resorted to within the scope of the following claims without de- `1 gfrom the spint of the invention or sacrificmg the advantageous characteristics hereof.

1. 'The combination, in a welding machine, l with electrode rolls for supplying welding current to the edges of a seam cleft of\a formed pipe, of laminated metalrolls for of the cleft together.

pipe laterally to fo'ice the edges l Y for engaging 2. In aweldingmachine, electrode rolls for supplyin Weldin to the edges of a seam cle in aormed pipe, an a laminated metal roll for engaging the pipe laterally to ,eiecta Weld. v

3. In an electric Welder, means for supplying current to the edges of a seam cleft in a formed pipe and means for preventin the ioW of current around theperiphery o the pipe comprising laminated meta rolls engag- 4. A Work-engaging roll for a continuous electric Welder, composed of stacked metal sheets.

. 5. A pressure roll for a continuous Welder having a Work engaging groove, said groove having a circumferential recess intermediate its edges.

6. Inv an electric Welder, a plurality of rolls a pipe to be Welded, said rolls being composed of metallic laminations or preventing the induction of current in the faces of said rolls by current circulating circumferentially of said pipe.

7. 'In a pipe Welder,a pressure roll engagving the pipe, said roll comprising metalhc laminations to linut the transformer eiect of current circulating circumferentially of the p1 8. In a continuous electric resistance pipe Welder, a roll for engagin the pi said roll comprising a plurality o clamped together to form a iluxupath of low reluctance in a plane perpendic tical diameter of said pige. v

In testimony whereof have hereunto set my hand.

JAMES V. CAPUTO.

metal aminations 

